This invention relates to hollow polyester filaments especially adapted to be readily split along their length so as to produce fibers of substantially smaller denier than the denier of the original hollow filament. More particularly, this invention relates to hollow polyester filaments that may be processed through conventional flocking machines, and then split to produce a product having a texture similar to suede made by napping of leather.
It is known in the art to produce flocked materials such as wallpaper fabric and the like by projecting the flocking material in an electrostatically charged condition against a substrate having an adhesive pattern. The electrostatically charged particles of flocking material are usually of somewhat longer length than diameter and are projected in such a manner that most of the particles become fixed to the adhesive by one end. The end opposite the end fixed to the adhesive is free to move about and yield to the touch.
It is known that texture of a flocked fabric is in part a function of the denier of the filaments protruding from the substrate. In general, the smaller the denier and more numerous the filaments the more suede-like the surface. However, it is difficult to produce and handle synthetic filamentary material of the denier desired in a product simulating suede. It has now been found that it is possible to produce a texture similar to suede by producing a hollow synthetic filamentary material having grooves that run in the longitudinal direction of the filament, chopping these filaments to the desired length and projecting the resulting particles onto an adhesive coated substrate and, after curing the adhesive, fracturing the filaments by suitable mechanical working such as abrasion caused by light sanding or the like.
The filaments of the present invention are especially adapted for use in producing suede-like products in that they are made of particular compositions having a particular molecular weight range (as indicated by relative viscosity). The molecular weight range is a limiting factor for the filaments, in that it must be sufficiently high that the filaments can be processed, e.g., chopped, without splitting, but sufficiently low that the filaments will split when the surface that they form on the substrate is mechanically worked, e.g., abraded. The filaments are of such dimensions that they may readily be produced on conventional spinning equipment [only the spinneret needs to be modified]. The filaments have a central continuous longitudinally extending void and a plurality of grooves and ridges that extend the length of the filaments.